Senior Java Backend Developer / Integration Engineer

We are looking for a 5 Senior Java Backend Developers / Integration Engineers to strengthen the team working in pharma sector, a strategic integration platform in the healthcare ecosystem. This role is ideal for someone who enjoys building reliable backend services, secure APIs, event-driven integrations, and cloud-connected data flows in a modern Java environment. Mission You will join a team responsible for the evolution of the solution, a multi-module platform built around integration, interoperability, security, and data exchange. Responsibilities Designing and implementing backend features in a modern Java stack Building and maintaining secure APIs and gateway flows Developing integrations with external systems and healthcare partners Working on event-driven communication and asynchronous processing Contributing to data persistence, migration, and operational reliability Supporting cloud-based data exchange patterns and AWS-connected services Ensuring code quality through unit and integration testing Collaborating closely with analysts, architects, and product stakeholders Tech Environment The current stack includes Spring Boot 4 Spring Cloud Gateway Spring WebFlux Spring Security Spring Data JPA MariaDB Flyway Redis JWT / OAuth2 Resource Server AWS SDK with S3 , Glue , Athena OpenAPI / Springdoc Jackson Parquet / Hadoop Maven JUnit 5 / Mockito Qualifications Strong experience in backend development with Java and Spring Solid knowledge of API design, security, and system integration Experience with relational databases such as MariaDB or MySQL Experience with messaging platforms such as Kafka Familiarity with cloud environments, ideally AWS Good understanding of authentication and authorization mechanisms such as JWT and OAuth2 A quality-driven mindset with attention to testing, maintainability, and production reliability The ability to work autonomously while collaborating effectively with a broader team Nice to Have Experience with Spring Cloud Gateway or API gateway patterns Experience with Redis Exposure to healthcare, interoperability, or regulated environments Experience with data pipelines or analytical storage flows using S3 / Athena / Glue Familiarity with hexagonal architecture or domain-driven design principles Benefits Strategic project with real business and integration impact Modern Java and Spring ecosystem Combination of backend engineering, integration, security, and cloud topics Collaborative team environment Opportunity to contribute to a platform used in a sensitive and meaningful domain Practical Information Location: Belgium / hybrid possible Engagement: freelance or employee, depending on profile Duration: long-term reinforcement for the team J-18808-Ljbffr